BeejiveIM - Best IM app out there, now with push notification support!
Convertbot - Best convertion app, and one of the best looking app out there!
Lose it! - Best calorie count app, great if you're trying to lose some pounds!
FlghtControl - Superb game, great for some casual game!

FacebookWunderRadio - Has most radio stations from around the world, great!.National Rail - See Departures/Arrivals/Delays at any UK station. Shows where trains are. Journey planner. Good app, just expensive.Sky NewsTwitterFon - Best twitter app Ive used so far.Backgrounder - Allows you to multi-taskNavigon GPS - Not too bad as a Sat Nav, really good actually, although tomtom is going to be better.